Operating mechanism for lifting jacks



Aug. 16, 1938.

OPERATING MECHANISM FOR LIFTING JACKS Filed March 1, 1937 Patented Aug. 16, 1938 UNITED STATES PATENT ()FFlCE OPERATING MECHANISM FOR LIFTING JACKS tion of Illinois Application March 1, 1937, Serial No. 128,342

2 Claims.

Ihis invention relates to improvements in operating mechanism for lifting jacks and it consists of the matters hereinafter described and mole particularly pointed out in the appended claims,

The lifting jacks with which the present inven ion is more particularly concerned, are of the embodying therein a shaft and a lever operated pawl and ratchet mechanism whereby the shaft may be turned in one direction or the other to raise or lower the load.

One of the objects of the present invention is to provide an improved mechanism of this kind, which is simple in construction, is positive in operation and is not only easy to shift from load-raising condition to load-lowering condition, but visibly presents to the operator, the condition for which the mechanism is set.

A further object of the invention is to provide a mechanism of this kind which may be assembled in a substantially grit-proof casing, so as to protect the interior mechanism from the abrading action of grit and the like and thus increase the period of usefulness of the mechanism without servicing or repair.

A further object of the invention is to provide an improved mechanism whereby the pawl may be rocked from one operative position to another with respect to the associated plunger from one side to the other of a line passing through the axes of said pawl and ratchet wheel respectively.

The above mentioned objects of the invention, as well as others, together with the several advantages thereof, will more fully appear as the specification proceeds.

In the drawing:

Fig. 1 is a side elevation of a jack operating mechanism, embodying the preferred form of the invention with parts of the associated casing shown in section better to illustrate the interior parts thereof.

Fig. 2 is a sectional view through the structure shown in Fig. 1, as taken on the line 22 of Fig. 1.

Fig. 3 is another sectional view through a part of the improved jack mechanism, as taken on the line 33 of Fig. 1.

Fig. 4 is a perspective view of a certain actuating member embodied in the improved mechanism and which will be more fully referred to later.

Fig. 5 is a view in side elevation, on a reduced scale, showing that side of the improved mechanism, opposite the side appearing in Fig. 1,

Referring now in detail to that embodiment of the invention illustrated in the accompanying drawing, 5 is a driving shaft of a conventional so-called journal jack and B is a ratchet wheel non-rotatively secured on a portion 7 of 5 said shaft, spaced from an extremity 8 thereof. As herein shown, said shaft portion 1 is of a rectangular cross section and the ratchet wheel 6 has a. corresponding opening that snugly fits thereon.

9 indicates a hollow casing or housing that encloses the ratchet wheel and is turnable about the axis of the shaft in opposite directions. As shown herein, said housing includes spaced side walls l0 and H respectively, front and rear walls l2 and 13 respectively, an end wall M rounded to be concentric with the axis of the shaft 5, and a second end wall l5. A socket 3| is made integral with one of the walls Ill-4| to receive a lever, whereby the casing is rocked back and forth-: about the axis of the shaft 5, in the manipulation of the jack for raising or lowering a load.

The ratchet wheel 6 is herein shown as having V shaped teeth on its periphery. l6 indicates a pawl journalled on a shaft or pin I! 25 spaced from and parallel with the shaft 5. The shaft [1 is suitably secured at its ends in openings provided therefor in the Walls l2 and I3 respectively and it is about the axis of said shaft that the pawl is rockable from one operative position to another, as will soon appear.

The pawl I6 is a two-ended one and therefore includes ends or arms l8 and I9 respectively arranged on the same side of the axis of the shaft I'I. Each pawl end is provided with V shaped 35 teeth l8 and I9 respectively for engagement with and disengagement from the similar teeth of the ratchet wheel. The pawl is of a substantially truncated triangular shape and its truncated or flat end 20, on the other side of the axis of the shaft or pin I! is arranged substantially parallel with a line extending between like points of the ends or arms I8 and I9.

2| indicates an actuating member in the form of a relatively short cylindrical member or pin slidable through the top end portions of the casing walls In and l I in a plane at a right angle to the line passing through the axes of the shafts 5 and I1 respectively. Said actuating member is 50 of a length greater than the distance between the associated end portions of the walls Ill and I i respectively at this point. The actuating member 2|, which is shown in perspective in Fig. 4, is provided at one side of its mid portion with a longitudinal groove 22 and is further provided at its mid portion with a transverse recess 23.

A set screw 24 is operatively engaged in an opening provided therefor in the wall l2 of the casing and this screw has a reduced end portion 25 which engages in the groove 22 of the member 2|. The screw 24 therefore, not only limits the endwise shifting movement of said member, but it also prevents said member from turning about its axis.

A yielding element in the form of a plunger 26 is disposed in the recess 23 and a spring 2! is interposed between said plunger and the bottom of said recess. Said spring normally urges the plunger outwardly so as yieldingly to hold its end in operative engagement with a part of the pawl end 20. On one of the walls l2l3 of the casing toward the walls Ill and Il thereof, are legends reading Up and Down respectively, as appears in Fig. 5. These legends visually indicate to the operator, by the position of the actuating member 2|, the setting of the pawl l6 for a raising or a lowering of the load being operated upon.

When the actuating member or pin 2| is pushed endwise from one limit of its movement to the other, as provided by the engagement of the screw end 25 in the groove 22, the spring pressed plunger 26 moves therewith in engagement with the pawl end 25. As the plunger approaches a line passing through the axes of the shafts 5 and H respectively, it yields or recedes into its recess and compresses its spring 21. So soon as the plunger passes said line, it is urged outwardly by its spring and rocks the pawl from one operative position to the other, as appears in full and dotted lines respectively in Fig. 1.

When the plunger is is disposed at one side of said line, as shown in Fig. 1, the teeth of the pawl end l9 are engaged with certain of the teeth of the ratchet wheel, at one side of said line passing through the axes of said shafts 5 and II. Thus, when the casing 9 is turned clockwise, as in Fig. l, the pawl causes the ratchet wheel to turn therewith to turn the shaft 5. When the casing is turned counterclockwise, the pawl is caused to click over the teeth of the ratchet wheel, the plunger 26 yielding in its recess to permit such movement.

In the assembly of the parts, the plunger 25 and its spring, the pawl l6 and the ratchet wheel 5 are introduced into the casing through an opening 28 in the casing Wall l3 of a diameter somewhat greater than that of the ratchet wheel. This opening is then closed by a flanged retainer plate 29. As shown herein, said plate has a pressed fit in said opening and a set screw 30, threaded partly in said plate and partly in the casing, locks said plate in place. The casing may be provided on its socket 3| with a lug 32 whereby the casing may be turned about the shaft 5 in the clicking direction, independently of the lever engaged in said socket.

It is apparent that the pawl is rocked from one operative position into the other by shifting the yielding means or plunger 26 from one side to the other of a line passing through the axes of the shafts 5 and M respectively, the yielding means or plunger operating against the pawl to let it click over the ratchet wheel on the back stroke.

While in describing the invention we have referred in detail to the form, arrangement and construction of the parts involved, the same is to be considered in the illustrative sense only so that we do not Wish to be limited thereto except as may be specifically set forth in the appended claims.

We claim as our invention:

1. In an operating mechanism of the kind described, a casing, a pawl pivotally mounted in the casing for a rocking movement from one operative position to another, a cylindrical actuating sliding member having a guided longitudinal movement through a part of said casing in two directions, said cylindrical member having a close i.

t within the ends of the casing to exclude dust and the like, said member having a longitudinal groove and a transverse recess therein, means carried by the casing and engaged in said groove and limiting the longitudinal movement of said member as well as preventing a turning movement of the same about its axis, and yielding means arranged in said recess and engaged with a part of said pawl for holding it in one operative position or the other, said yielding means in the movement of the actuating member from one limit of movement to the other, operating upon said pawl part for rocking the pawl from one operative position to the other.

2. In an operating mechanism of the kind described, a casing, a pawl pivotally mounted in the casing for a rocking movement from one operative position to another, an actuating sliding member having a guided longitudinal movement through a part of said casing in two directions, said member having a close fit within the ends of the casing to exclude dust and the like, said memher having a longitudinal groove and a transverse recess therein, means carried by the casing and engaged in said groove and limiting the longitudinal movement of said member, and yielding means arranged in said recess and engaged with a part of said pawl for holding it in one operative position or the other, said yielding means in the movement of the actuating member from one limit of movement to the other, operating upon said pawl part for rocking the pawl from one operative position to the other.

GEORGE E. TINTERA. WILLIAM E. GAHL.

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